During normal pregnancy, the gastrointestinal tract and its appendages undergo remarkable anatomical, physiological, and functional changes. These changes, which are discussed in detail in Chapter 5, Gastrointestinal Tract, can appreciably alter clinical findings normally relied on for diagnosis and treatment of gastrointestinal disorders. One example is nausea and vomiting, which is frequent early in normal pregnancy. If these symptoms persist or develop later, they may be erroneously attributed to normal physiological changes, and a serious pregnancy complication or nonobstetrical problem may be overlooked. In another example, most obstetricians, but not most internists or gastroenterologists, are aware that epigastric or right upper quadrant pain can be an ominous sign of severe preeclampsia. Finally, as pregnancy progresses, gastrointestinal symptoms become more difficult to assess, and physical findings are often obscured by the large uterus, which displaces abdominal organs and can alter the location and intensity of pain and tenderness.
In general, gastrointestinal tract evaluation can be completed without reliance on radiological techniques.
Fiberoptic endoscopic instruments have revolutionized diagnosis and management of most gastrointestinal conditions. They are particularly well suited for use during pregnancy. Cappell (2006) estimates that nearly 20,000 pregnant women annually have indications for endoscopy to evaluate the esophagus, stomach, duodenum, and colon. The proximal jejunum can also be studied, and the ampulla of Vater cannulated to perform endoscopic retrograde cholangiopancreatography—ERCP (Al-Hashem and colleagues, 2008). Experience in pregnancy with videocapsule endoscopy for small-bowel evaluation is limited (Storch and Barkin, 2006). In most endoscopies, sedation is required, and especial considerations are given to complications unique to pregnancy.
Upper gastrointestinal endoscopy is used for management as well as diagnosis of a number of problems. Common bile duct exploration and drainage are used for choledocholithiasis as described in Chapter 50, Gallbladder Disorders. It is also used for sclerotherapy as well as placement of percutaneous endoscopic gastrostomy (PEG) tubes. A number of concise reviews have been provided (Bruno and Kroser, 2006; Cappell, 2006; Gilinsky and Muthunayagam, 2006).
Flexible sigmoidoscopy can be used safely in pregnant women (Siddiqui and Denise-Proctor, 2006). Colonoscopy is used to view the entire colon and distal ileum for diagnosis and management of inflammatory bowel disease. Bowel preparation is completed using polyethylene glycol electrolyte or sodium phosphate solutions with care to avoid serious maternal dehydration. Reports of colonoscopy during pregnancy are limited, but preliminary results are encouraging, and it should be performed if indicated (Cappell, 2003).
Noninvasive Imaging Techniques
The obvious technique for gastrointestinal evaluation is abdominal sonography. Because computed tomography (CT) use is limited in pregnancy due to radiation exposure, magnetic resonance (MR) imaging is now commonly used for evaluating the abdomen and retroperitoneal space. These and other imaging modalities, and their safety for use in pregnancy, are considered in detail in Chapter 41, Imaging Techniques.